Nephropidae NEPHROPIDAE True Lobsters and Lobsterettes Iagnostic Characters: Moderate to Dlarge-Sized Crustaceans
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click for previous page 982 Lobsters Nephropidae NEPHROPIDAE True lobsters and lobsterettes iagnostic characters: Moderate to Dlarge-sized crustaceans. Body tubular, surface almost naked or covered with thick rostrum well 1st pincer fur. Carapace (or “head”) with a well-devel- developed oped rostrum, ornamented with spines or enlarged first 3 legs nodules, occasionally smooth. Eyes usually with 1 well developed and black, or small and lack- pincers ing pigmentation, or even absent. Antennae very long and thread-like; antennal scale, if present, with inner margin unarmed and curved. First 3 pairs of legs forming true 2 pincers, with the first pair greatly en- larged and long. Both abdomen and tail fan well developed and powerful. Abdomen smooth or variously sculptured, pleura end- 3 ing in acute ventral tooth. Tail fan entirely hardened, telson with fixed spines and 4 posterior margin broadly convex. Colour: with the typical coloration of deep-sea crus- taceans - from white to pink or red, some species with special markings (usually red 5 and/or white) on body; setae or hairs, if pre- sent, are light brown. Habitat, biology, and fisheries: All species are deep-sea forms and found at depths from 150 to more than 1 893 m. Their adult sizes median are ranging from 5 cm to over 40 cm. They carina are bottom-dwellers with a preference for soft substrate. Some species are known to live in self-made burrows. The sexes are eas- pleura with ily distinguished by the position of the ventral tooth gonopores, which are situated at the bases of the third and fifth legs in the females and males, respectively. In addition, the first pleopods (“legs” of the abdomen) of males are transformed into a strong and rigid pen- tail fan hardened like copulatory organ while they are reduced and thread-like in females. The females bear large and colourful eggs (white, blue or red, and other colours) on the ventral side of the abdomen. They seem to have a long incubation period, but a short larval development. At present, none of the species of this family is of significant commercial importance in the Western Central Pacific. However, the large size of several species and the fact that some of them are commonly caught on the basis of exploratory trawling suggest that they may have some commercial potential with the development of deep-sea fisheries. This is especially the case with members of the genus Metanephrops, which are treated here in separate species accounts. gonopore leg 3 leg 4 abdominal sternite leg 5 copulatory stylets reduced, thread-like sperm gonopore receptacle male female male female bases of last 3 legs in nephropids first pleopods of nephropids Nephropidae 983 1st pincers very unequeal Similar families occurring in the area Thaumastochelidae: body somewhat flattened dorsoventrally; 1 antennal scale with several large teeth along inner margin; first pair of pincers very unequal; abdominal pleura short, quadran- gular and not ending in a point; telson unarmed. antennal scale Enoplometopidae: body distributed with tufts of long stiff hairs; 2 second and third legs forming false pincers; telson bearing movable spines. 3 Polychelidae: carapace box-like, rostrum absent or rudimen- tary; first 4 or all legs with pincers, first pair long but slender; telson pointed. 4 Glypheidae: body somewhat flattened dorsoventrally; eyes 5 inserted on a median elevation of cephalon; first 2 legs forming pleura false pincers. quadrangular Synaxidae: body somewhat flattened dorsoventrally and hairy;all legs simple and without pincers, the first pair heavier than the others; antennae whip-like and shorter than carapace; posterior half of tail fan soft and flexible. 1 Thaumastochelidae 1st leg long and 1 2nd and 3rd legs slender first 4 or all with false legs with pincers 2 pincers 3 2 4 3 5 4 tufts of long stiff hairs 5 movable spines telson telson pointed Enoplometopidae no pincers Polychelidae 2 antenna 1 short rostrum 3 4 5 5 4 posterior half of 2 3 simple dactylus tail fan soft 1 false pincers Glypheidae Synaxidae 984 Lobsters Palinuridae: carapace without rostrum or with rostrum reduced to a small spine, but with a pair of large frontal horns over the eyes; antennae very long and thick, whip-like or spear-like; legs without true pincers and first pair generally not enlarged (except in Justitia); posterior half of tail fan soft and flexible. Scyllaridae: body strongly flattened dorsoventrally; rostrum absent or rudimentary; eyes enclosed by distinct orbits; antennae plate-like; legs without true pincers and none of them enlarged; posterior half of tail fan soft and flexible. no pincers antenna 1 plate-like 2 frontal horns 1 3 2 no 3 4 pincers 4 5 5 body flat posterior half posterior half of tail fan soft of tail fan soft Palinuridae Scyllaridae Key to the genera of Nephropidae occurring in the area 1a. Eyes large and black; antennal scale present; body provided with some spines but never uniformly spinulose (Fig. 1) ...............................Metanephrops 1b. Eyes minute, cornea lacking pigmentation ............................→ 2 2a. Antennal scale present; body more or less uniformly spinulose and not covered with soft pubescence (Fig. 2) ...................................Acanthacaris (a single species, A. tenuimana, in the area) 2b. Antennal scale absent; body not uniformly spinulose but covered with thick pubescence (Fig. 3) ...........................................Nephropsis antennal scale antennal scale Fig. 1 Metanephrops Fig. 2 Acanthacaris Fig. 3 Nephropsis Nephropidae 985 Key to the species of Metanephrops occurring in the area 1a. Carapace rather uniformly spinu- lose (Fig. 4a); dorsal surface of → no uropods covered with spinules ..... 2 spinules 1b. Carapace smooth between the between ridges and large spines (Fig. 4b); large → spines uropods unarmed dorsally ........ 4 surface and uniformly ridges spinulose 2a. Abdominal segments each with 2 transverse grooves (Fig. 5a); large pincer with finger dis- tinctly longer than palm a) Metanephrops neptunus b) Metanephrops sibogae (Fig. 6a) ......Metanephrops neptunus Fig. 4 carapace (dorsal view) 2b. Abdominal segments each with 1 transverse groove only (Fig. 5b, c); large pincer with finger shorter than palm (Fig. 6b) .....→ 3 3a. Abdomen with deep longitudinal furrows (Fig. 5b); large pincer covered with sharp tubercles ..................................Metanephropsarafurensis 3b. Abdomen without distinct longitudinal furrows (Fig. 5c); large pincer finely granular to nearly smooth ..............................Metanephropsaustraliensis longitudinal furrows finger finger 2 1 transverse transverse palm grooves groove palm a) Metanephrops b) Metanephrops c) Metanephrops neptunus arafurensis australiensis a) Metanephrops b) Metanephrops neptunus australiensis Fig. 5 first 3 abdominal segments (dorsal view) Fig. 6 large pincer 4a. Abdomen with distinct transverse and longitudinal grooves (Fig. 7); large pincers distinctly ridged (Fig. 8a), with outer border flat ..........................→ 5 4b. Abdomen smooth or with only narrow transverse grooves; large pincer smooth or weakly ridged (Fig. 8b), with outer border always angular .........................→ 6 5a. Elevated parts of abdomen naked and smooth (Fig. 7a) ........Metanephropsandamanicus 5b. Elevated parts of abdomen coarse and pubescent (Fig. 7b) ........Metanephropsvelutinus longitudinal elevated grooves pubescent parts naked and distinctly smooth ridged weakly ridged a) Metanephrops a) Metanephrops andamanicus b) Metanephrops velutinus b) Metanephrops andamanicus sibogae Fig. 7 abdomen (dorsal view) Fig. 8 large pincer 986 Lobsters 6a. Abdomen smooth, without grooves (Fig. 9a) .................Metanephropssibogae 6b. Abdomen with narrow transverse grooves (Fig. 9b, c) ......................→ 7 surface smooth no transverse transverse groove on 1st groove on 1st segment segment a) Metanephrops sibogae b) Metanephrops thomsoni c) Metanephrops sinensis Fig. 9 abdomen (dorsal view) 7a. Two postorbital spines present (Fig. 10a); large pincers with inner margin naked but often bearing some large spines (Fig. 11a); first abdominal segment generally without distinct transverse grooves (Fig. 9b) .....................Metanephropsthomsoni 7b. Three postorbital spines present (Fig. 10b); large pincers without large spines along inner margin, lateral margin of movable fingers bearing a brush of setae (Fig. 11b); first abdominal segment usually with short, lateral, transverse grooves (Fig. 9c) ..... .........................................Metanephrops sinensis 2 postorbital 3 postorbital spines spines brush of setae large spines a) Metanephrops thomsoni b) Metanephrops sinensis a) Metanephrops thomsoni b) Metanephrops sinensis Fig. 10 carapace (lateral view) Fig. 11 large pincer Key to the species of Nephropsis occurring in the area 1a. Rostrum without lateral teeth (Fig. 12a) ....................Nephropsisensirostris 1b. Rostrum with lateral teeth (Fig. 12b-d) ...............................→ 2 2a. Rostrum with 2 pairs of lateral teeth (Fig. 12b) ..........................→ 3 2b. Rostrum with 1 pair of lateral teeth (Fig. 12c, d) ..........................→ 4 2 pairs of 1 pair of subdorsal lateral teeth lateral teeth subdorsal ridges no lateral ridges lacking teeth on spinous spines rostrum a) Nephropsis ensirostris b) Nephropsis sulcata c) Nephropsis serrata d) Nephropsis stewarti Fig. 12 carapace (dorsal view) Nephropidae 987 3a. Abdomen with a median longitudinal carina (Fig. 13) ...............Nephropsissulcata 3b. Abdomen without a median